Astronaut Edwin (Buzz) E. Aldrin Jr., pilot of the Apollo 11 mission, poses beside a flag on the surface of the moon. One space policy analyst says the space shuttle program was the natural successor to the Mercury, Gemini and Apollo programs and evolved humans' ability to live and work in space.

No longer would spacecraft be used once and then discarded. In NASA videos to promote the shuttle, narrators intoned that "the United States can no longer afford the luxury of the throw-away rocket." After all, jet planes could fly again and again. Now, so too would spaceships, and the frontier of space would be opened up for business, research and even private citizens.

At least that was NASA's vision of the shuttle as it sold the idea of the new spacecraft to decision-makers in Washington, D.C., decades ago.

NASA's Apollo moonshot had been a spectacular success — but expensive. If space travel had a future, the next program had to be cost-effective.

The agency enlisted economists to make the case for this new reusable vehicle.

"You know, it was just thrilling to be that close to such an interesting project," says Edward Greenblat. As a young Ph.D. student back in the 1970s, he worked on one influential economic analysis.

No one had built anything like the shuttle before, so figuring out its costs and benefits wasn't easy. "There were a whole bunch of things on the drawing board and we had to sift through them and come up with what we thought would be the most cost-effective design," Greenblat recalls.

The Space Shuttle Business

A lot of the economic arguments for the shuttle came down to the satellite business — for the military, communications and science missions. The shuttle's large payload bay could carry up multiple satellites at a time. And astronauts could repair satellites or bring them home to be refurbished.

On April 12, 1981, the first shuttle lifted off. Now, 30 years later, the shuttles are just months away from becoming museum exhibits as the shuttle program finally winds down.

"If you want to answer the question, 'Is it a success or a failure?' one way to do that is to ask the question, 'Well, what was it supposed to do, and at what cost?' And then compare what the data says to what those expectations were," says Roger Pielke Jr., a science policy analyst at the University of Colorado, Boulder.

"Where NASA really fell short was in the flight rate," Pielke says. "In the early 1970s, when promising what they were going to deliver, they were talking about a flight rate of 48 shuttle flights per year, at a marginal cost per launch of something like $15 million."

Instead of going up nearly once a week, the reality is that the shuttles have flown about four times a year — at an average cost of about $1.5 billion.

Pielke recently added up the entire cost of the shuttle program. "In 2010 dollars, so converting everything to current dollars, in one round number, it's a $200 billion effort," he says. "And that works out somewhere between $200 and $250 million per person launched into space. So any way that you slice the numbers it has been a pretty expensive undertaking these past 40 years."

The spaceships took longer than people had thought to get turned around to go up again. The satellite business didn't turn out as expected.

The shuttles were also grounded for years after seven people — including a schoolteacher — died in the Challenger accident and seven more people died in the Columbia tragedy.

Even if space shuttle launches had become common enough that most of the public ignored them, these two accidents were a painful demonstration that spaceflight was still far from routine.

But Pielke says the shuttle did deliver on some of its promises: "At the highest level, it does fulfill the promise of being a reusable spacecraft. And in that sense it has been really a tremendous success."

'A Multipurpose Work Vehicle'

The shuttle allowed the U.S. to forge international partnerships to build a huge, orbiting space station — where astronauts live in spacious splendor for months at a time — and also allowed the country to retain its position as the world leader in spaceflight after the Apollo era.

"As far as the specific vehicle and what it can do, it has turned out exactly as we envisioned," says Bob Thompson, who ran the shuttle program from 1970, when the shuttle was still being conceived, until after the first flight.

Some of the early cost projections were pie-in-the-sky and relied on a number of missions that turned out to be unrealistically high, he says.

But he believes the shuttle has evolved humans' ability to live and work in space and was the natural successor to Mercury, Gemini, and Apollo.

"The shuttle provided the country a national capability it could not get otherwise," says Thompson. "The shuttle gave the country a very capable work vehicle to go into low Earth orbit and do everything from carrying experiments there to launching satellites from there, to building space stations, to building telescopes like Hubble. It was a multipurpose work vehicle."

Thompson expects that history will remember the shuttle kindly.

Meanwhile, the NASA workforce is looking ahead to its future, trying to figure out what's next. Its leaders have set their sights on deep space — perhaps a trip to an asteroid or back to the moon.

The bread and butter of the shuttle's work will be turned over to private companies. They're developing new rockets and capsules for quick trips up close to Earth, like to the orbiting station — and promising to usher in a new era that will make space more accessible than ever before.

SIMON: This is how the crew aboard the Space Shuttle Atlantis woke up this morning, to "Viva La Vida" - forgive me, "Viva La Vida," by Coldplay. Atlantis, of course, was the last shuttle flight ever. Forty years ago, when NASA was trying to sell the idea of the shuttle, it promised it would usher in a new age of travel. As the program heads into retirement, NPR's Nell Greenfieldboyce compares the promises to reality.

NELL GREENFIELDBOYCE: If you opened up a copy of the magazine "Popular Science" back in 1974, you'd see an artist's conception of a blast-off for the new spaceship that NASA was building. The headline: "Reusable Space Shuttle, Our Biggest Bargain In Out-Of-This-World Research." The era of cheap, routine space flight was about to begin.

(SOUNDBITE OF NASA VIDEO)

NARRATOR: The United States can no longer afford the luxury of the throwaway rocket. Our answer to this challenge is the space shuttle. At home in the vacuum of space, and the atmosphere of earth.

GREENFIELDBOYCE: That's a NASA promotional video. The space shuttle would land on a runway instead of splashing in the ocean, making getting into a spaceship more like getting on an airplane - opening up all kinds of new opportunities in satellite technology and scientific research.

(SOUNDBITE OF NASA VIDEO)

NARRATOR: Space and space technology are assuming an ever more important role in our modern civilization. The instrument by which routine access to space will be achieved is the United States space shuttle.

GREENFIELDBOYCE: Now, NASA's moon shot had been a spectacular success, but expensive. If space travel had a future, any new vehicle had to be cost-effective. So the agency enlisted economists to make the case for the shuttle. Edward Greenblat was a young Ph.D. student who worked on one influential study back in the early 1970s.

EDWARD GREENBLAT: You know, it was just thrilling to be that close to such an interesting project.

GREENFIELDBOYCE: No one had built anything like the shuttle before.

GREENBLAT: There were a whole bunch of things on the drawing board, and we had to sift through them and come up with what we thought would be the most cost-effective design.

GREENFIELDBOYCE: A lot of the economic arguments for the shuttle came down to the satellite business. For the military, communications and science missions, the shuttle's large payload bay could carry up multiple satellites at a time. And astronauts could repair satellites, or bring them home to be refurbished.

(SOUNDBITE OF SPACE SHUTTLE COMMUNICATION)

GREENFIELDBOYCE: On April 12, 1981, the first shuttle lifted off.

(SOUNDBITE OF NASA VIDEO)

NARRATOR: We are beginning a new and exciting age, signaled by the flight of Columbia into Earth's orbit.

GREENFIELDBOYCE: Thirty years later, people are asking if the age of the space shuttle lived up to its promise.

ROGER PIELKE JR.: If you want to answer the question, is it a success or failure? one way to do that is to ask the question, well, what was it supposed to do, and at what cost? And then compare what the data says to what those expectations were.

GREENFIELDBOYCE: That's Roger Pielke Jr., a science policy analyst at the University of Colorado in Boulder.

PIELKE: Where NASA really fell short was in the flight rate. In the early 1970s, when promising what they were going to deliver, they were talking about a flight rate of 48 shuttle flights per year, at a marginal cost per launch of something like $15 million.

GREENFIELDBOYCE: Instead of going up nearly once a week, the reality is that the shuttles have flown about four times a year, at an average cost of about $1.5 billion. Pielke recently added up the entire cost of the shuttle program - no small feat - and here's what he found.

PIELKE: In 2010 dollars - so converting everything to current dollars - in one round number is a $200 billion effort, and that works out somewhere between $200 and $250 million per person launched into space. So any way that you slice the numbers, it has been a pretty expensive undertaking these past 40 years.

GREENFIELDBOYCE: The spaceships were reusable, but they took much longer than people had thought to get turned around to go up again. They were also grounded for years after seven people, including a schoolteacher, died in the Challenger accident. And then seven more people died in the Columbia tragedy.

Even if space shuttle launches had become common enough that most of the public ignored them, these accidents were a painful demonstration that space flight was still far from routine. But Pielke says the shuttle did deliver on some of its promises.

PIELKE: You know, at the highest level, it does fulfill the promise of being a reusable spacecraft - and in that sense has been, really, a tremendous success.

GREENFIELDBOYCE: The shuttle allowed the U.S. to forge international partnerships, to build a huge orbiting space station. Astronauts live there in spacious splendor for months at a time. And the shuttle allowed the U.S. to retain its position as the world leader in space flight after the Apollo era. Pielke says to many people, those are valuable achievements.

PIELKE: There's a lot of intangible benefits to the space shuttle program. And the question of, was $200 billion worth it? is really kind of an ink blot test.

BOB THOMPSON: As far as the specific vehicle and what it can do, it's turned out exactly as we envisioned.

GREENFIELDBOYCE: That's Bob Thompson. He ran the shuttle program from 1970, when it still being conceived, until after the first flight. Yes, he says, some of the early cost projections were pie in the sky. But the shuttle has evolved our ability to live and work in space.

THOMPSON: The shuttle provided the country a national capability it could not get otherwise. The shuttle gave the country a very capable work vehicle to go into low Earth orbit and do everything from carrying experiments there to launching satellites from there, to building space stations, to building telescopes like Hubble. It was a multipurpose work vehicle.

GREENFIELDBOYCE: Thompson believes that history will remember the shuttle kindly. Meanwhile, NASA is looking ahead to its future, trying to figure out what's next. It's set its sights on deep space. The bread and butter of the shuttle's work - quick trips up close to Earth, like to the orbiting space station - will be turned over to private companies. They're developing new rockets and capsules, and promising to usher in a new era that will make space more accessible than ever before.